The invention concerns a radio-controlled timepiece movement and method of assembly.
A radio-controlled timepiece movement is known from Allgaier et al. U.S. Pat. No. 4,645,357 (corresponding to DE 35 10 861). That movement includes a light-barrier for detecting the displayed time in order to implement an automatic correction either at the beginning of operation or during operation. The movement is distinguished by virtue of a compact structure and a high level of operational reliability because the light-barrier is integrated into the gear train of the movement itself. For the construction of a transmission-type light barrier arrangement, the 1ight barrier elements, i.e., a radiation transmitter and an opposing radiation receiver, are secured in through bores formed in a printed circuit board and a front housing wall of the movement, respectively.
Non-encased radiation transmitters in the form, for example, of diodes (in the form of chips) emitting infra-red light can also be glued in electrically conducting relationship directly onto a conductor track lining of the printed circuit board and electrically connected to another conductor track of the same printed circuit board by means of a bond wire which extends downwardly in an arc shape.
Then however that structure must be embedded in a radiation permeable plastic material, to provide for mechanical protection for same. It will be noted that overall this takes up a really large amount of space as the plastic material has to cover the high arc of the bond wire above the free surface of the chip down into the plane of the conductor track, and that results in both a wide and also a high mound of casting material. That is a nuisance, in particular, if the radio-controlled timepiece movement is to be of an extremely compact design configuration, for example so that it can be disposed in a wristwatch casing. The smaller the movement becomes, the correspondingly more complicated is the adjustment of the wheels which project into the light barrier arrangement, in terms of their respective angular position for transmitting light therethrough.
Therefore an object of the present invention is to develop a radio-controlled movement of the general kind set forth, that can be of a smaller design and more easily assembled.